On 14/08/2012 20:56, polygonum wrote:
On Tue, 14 Aug 2012 20:49:32 +0100, Bob Eager wrote:

On Tue, 14 Aug 2012 19:48:46 +0100, newshound wrote:

When I had my last "work" medical, the consultant was lamenting the fact
that she wasn't allowed to use a mercury sphygmomanometer at NHS
hospitals any more and had had to go over to an electronic one, which
she regarded as a poor substitute.

My GP (who is pretty 'up to date') prefers a mercury one and still uses
such.


Pity the people who maintain them:


Description:
A 37-year-old man worked for up to 60hr a week for 3yr in a small, hot,
poorly ventilated room (volume 140 cu.m (approx)). He spent 5-10% of his
time repairing sphygmomanometers containing mercury. For a year he
complained of worsening neuropsychiatric symptoms including tremor,
forgetfulness and irritability. A 24-hour urine collection showed
mercury conc of 200 nmol/mmol creatinine (400microg/g). As his urinary
mercury conc fell to more normal values his symptoms improved. 3 other
workers working in the same premises were also found to have elevated
urinary mercury levels, but no symptoms. Examination of the premises
showed contamination of work surfaces. Decontamination was tried, but
6mo afterwards an environmental survey showed levels in the workshop to
be 6 to 10 times the recommended limit. Other sphygmomanometer workshops
in Scotland were examined and similar deficiencies found. In 2 premises
work was prohibited until the deficiencies had been remedied.

http://www.evidence.nhs.uk/document?...hygmomanometer


Scary. Anyone who did A level chemistry forty or fifty years ago would
have been very well aware of the risks. Now you have to have safety
screens when the teacher is using dilute acids. Somewhere along the way
we lost the science.

In article m,
newshound writes:
Scary. Anyone who did A level chemistry forty or fifty years ago would
have been very well aware of the risks. Now you have to have safety
screens when the teacher is using dilute acids. Somewhere along the way
we lost the science.

I'm told practicals are a thing of the past in most schools,
not due to H&S, but due to no time left after covering everything
that's centrally mandated nowadays.

However, it reminds me of a lecture at university, Materials Science
topic. Lecturer started with a balloon (blown up) in one hand, and
a pin in the other, and jokingly said
"I should really have a safety screen for this!"
When he stuck the pin in the balloon and it burst, the knot shot off
and got me in the eye, which was quite painful.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 15/08/2012 21:40, Andrew Gabriel wrote:
In article m,
newshound writes:
Scary. Anyone who did A level chemistry forty or fifty years ago would
have been very well aware of the risks. Now you have to have safety
screens when the teacher is using dilute acids. Somewhere along the way
we lost the science.

I'm told practicals are a thing of the past in most schools,
not due to H&S, but due to no time left after covering everything
that's centrally mandated nowadays.

However, it reminds me of a lecture at university, Materials Science
topic. Lecturer started with a balloon (blown up) in one hand, and
a pin in the other, and jokingly said
"I should really have a safety screen for this!"
When he stuck the pin in the balloon and it burst, the knot shot off
and got me in the eye, which was quite painful.

;-)

I am sure we did plenty of things at school that were dodgy then - let
alone now...

Making Nitrogen Triiodide was fun (we were allowed to make it on the
understanding none of it left the lab... not sure is there were any of
us that did not spirit at least some out!)

A demo of converting copper coins into "silver" by rubbing with Millon's
Solution (a Mercury and Nitric acid reagent IIRC) - apparently this was
a technique that kept the teacher in question in cheap beer at a local
pub through his university days, due to the peculiarities of pre decimal
coinage.

The manufacture of bromide gas was also entertaining when someone forgot
to hook the reaction vessel up to the gas jar and filled the lab instead ;-)

And chucking various reactive metals in water was always fun.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article ,
John Rumm writes:
On 15/08/2012 21:40, Andrew Gabriel wrote:
In article m,
newshound writes:
Scary. Anyone who did A level chemistry forty or fifty years ago would
have been very well aware of the risks. Now you have to have safety
screens when the teacher is using dilute acids. Somewhere along the way
we lost the science.

I'm told practicals are a thing of the past in most schools,
not due to H&S, but due to no time left after covering everything
that's centrally mandated nowadays.

However, it reminds me of a lecture at university, Materials Science
topic. Lecturer started with a balloon (blown up) in one hand, and
a pin in the other, and jokingly said
"I should really have a safety screen for this!"
When he stuck the pin in the balloon and it burst, the knot shot off
and got me in the eye, which was quite painful.

;-)

I am sure we did plenty of things at school that were dodgy then - let
alone now...

Making Nitrogen Triiodide was fun (we were allowed to make it on the
understanding none of it left the lab... not sure is there were any of
us that did not spirit at least some out!)

I made it at home, Scrubbs household ammonia, Iodine, and tincture
of iodine (potassium iodide solution) bought from the chemist.

Due to my impatience waiting for it to dry, I managed to flick a
fair amount of it on the floor before it was dry, which resulted
in an interesting crackling effect later when walking over it.

Normally it was pretty harmless, but someone did manage to make
enough in the fume cupboard that it blow up the filter funnel when
it was later being cleared away. I think words were said at that
point, but it was very much about being more careful, and not
dampening the enthusiasm for such activities. Actually, looking
back, our chemistry teachers allowed us to do some quite risky
things like dropping sodium into acid (by a remote control scheme
we had to build for the purpose). That was really spectacular,
and we could see why the text books all say to never do this.
One of the chemistry teachers had a license to manufacture
fireworks (and did so regularly), so they were well aware of the
dangers, but also the enthusiasm they could generate in the subject.

A demo of converting copper coins into "silver" by rubbing with Millon's
Solution (a Mercury and Nitric acid reagent IIRC) - apparently this was
a technique that kept the teacher in question in cheap beer at a local
pub through his university days, due to the peculiarities of pre decimal
coinage.

The manufacture of bromide gas was also entertaining when someone forgot
to hook the reaction vessel up to the gas jar and filled the lab instead ;-)

And chucking various reactive metals in water was always fun.

In my brother's year, there used to be a game of "chicken" which
played out during chemistry lessons. At the start, someone got a
beaker out of the cupboard, and poured some chemical into it from
the bench (we had lots of chemical reagent bottles on the benches,
although nothing particularly harmful was left out permanently).
The beaker was passed on to the next person to add some other
chemical. If you were lucky, nothing much happened. If you were
unlucky, it frothed up all over the bench, and you then had to
hide the mess or if noticed, quickly think of a pausible excuse.

I just can't imagine any of this happening today. Chemistry must
be very boring...

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 17/08/2012 16:30, John Rumm wrote:
On 15/08/2012 21:40, Andrew Gabriel wrote:
In article m,
newshound writes:
Scary. Anyone who did A level chemistry forty or fifty years ago would
have been very well aware of the risks. Now you have to have safety
screens when the teacher is using dilute acids. Somewhere along the way
we lost the science.

I'm told practicals are a thing of the past in most schools,
not due to H&S, but due to no time left after covering everything
that's centrally mandated nowadays.

However, it reminds me of a lecture at university, Materials Science
topic. Lecturer started with a balloon (blown up) in one hand, and
a pin in the other, and jokingly said
"I should really have a safety screen for this!"
When he stuck the pin in the balloon and it burst, the knot shot off
and got me in the eye, which was quite painful.

;-)

I am sure we did plenty of things at school that were dodgy then - let
alone now...

Making Nitrogen Triiodide was fun (we were allowed to make it on the
understanding none of it left the lab... not sure is there were any of
us that did not spirit at least some out!)

I think you mean ammonium tri-iodide made by dissolving iodine in 880
ammonia solution. This forms a brown precipitate that is incredibly
unstable particularly when dried.

--
Peter Crosland

I am sure we did plenty of things at school that were dodgy then - let
alone now...

Thanks for putting me in mind of school chemistry lessons.

Our chemistry teacher was employed during the war in
munitions/explosives development. He was responsible for my interest in
the subject, leading to a lifetime working in jobs related to chemistry.

At the end of the year, when there was a lul after exams and before the
formal end of term, he would carry out some practical demonstrations
which served to educate, but also entertain. The most vigourous of which
(as I remember from 40+ years ago) was creating some thermite in a
bucket at the back of the lab out of the view of the other school
buildings.

The big bang and the huge cloud of smoke gave him away, however. His
palour and reaction to the event told us he got the proportions wrong,
and I doubt he repeated the trick. It was entertaining though.

Al.

On 17/08/2012 18:36, Peter Crosland wrote:
On 17/08/2012 16:30, John Rumm wrote:
On 15/08/2012 21:40, Andrew Gabriel wrote:
In article m,
newshound writes:
Scary. Anyone who did A level chemistry forty or fifty years ago would
have been very well aware of the risks. Now you have to have safety
screens when the teacher is using dilute acids. Somewhere along the way
we lost the science.

I'm told practicals are a thing of the past in most schools,
not due to H&S, but due to no time left after covering everything
that's centrally mandated nowadays.

However, it reminds me of a lecture at university, Materials Science
topic. Lecturer started with a balloon (blown up) in one hand, and
a pin in the other, and jokingly said
"I should really have a safety screen for this!"
When he stuck the pin in the balloon and it burst, the knot shot off
and got me in the eye, which was quite painful.

;-)

I am sure we did plenty of things at school that were dodgy then - let
alone now...

Making Nitrogen Triiodide was fun (we were allowed to make it on the
understanding none of it left the lab... not sure is there were any of
us that did not spirit at least some out!)

I think you mean ammonium tri-iodide made by dissolving iodine in 880
ammonia solution.

Indeed another name for the same thing... NI3

(IIRC we made it with crystallized iodine, which then allows you to pour
off the amonia once "activated" - its then stable so long as its kept wet)

aka Nitrogen iodide, Ammonia triiodide, Triiodine nitride, and others...

This forms a brown precipitate that is incredibly
unstable particularly when dried.

Yes and nice puff of purple smoke... and a yellow stain on anything that
it detonates on.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 17/08/2012 21:11, John Rumm wrote:
On 17/08/2012 18:36, Peter Crosland wrote:
On 17/08/2012 16:30, John Rumm wrote:
On 15/08/2012 21:40, Andrew Gabriel wrote:
In article m,
newshound writes:
Scary. Anyone who did A level chemistry forty or fifty years ago would
have been very well aware of the risks. Now you have to have safety
screens when the teacher is using dilute acids. Somewhere along the
way
we lost the science.

I'm told practicals are a thing of the past in most schools,
not due to H&S, but due to no time left after covering everything
that's centrally mandated nowadays.

However, it reminds me of a lecture at university, Materials Science
topic. Lecturer started with a balloon (blown up) in one hand, and
a pin in the other, and jokingly said
"I should really have a safety screen for this!"
When he stuck the pin in the balloon and it burst, the knot shot off
and got me in the eye, which was quite painful.

;-)

I am sure we did plenty of things at school that were dodgy then - let
alone now...

Making Nitrogen Triiodide was fun (we were allowed to make it on the
understanding none of it left the lab... not sure is there were any of
us that did not spirit at least some out!)

I think you mean ammonium tri-iodide made by dissolving iodine in 880
ammonia solution.

Indeed another name for the same thing... NI3

(IIRC we made it with crystallized iodine, which then allows you to pour
off the amonia once "activated" - its then stable so long as its kept wet)

aka Nitrogen iodide, Ammonia triiodide, Triiodine nitride, and others...

This forms a brown precipitate that is incredibly
unstable particularly when dried.

Yes and nice puff of purple smoke... and a yellow stain on anything that
it detonates on.

Indeed but as I recall it was NH4I3 but there is some doubt because it
is so unstable it is very hard to work with.


--
Peter Crosland

On 17/08/2012 22:12, Peter Crosland wrote:
On 17/08/2012 21:11, John Rumm wrote:
On 17/08/2012 18:36, Peter Crosland wrote:
On 17/08/2012 16:30, John Rumm wrote:
On 15/08/2012 21:40, Andrew Gabriel wrote:
In article m,
newshound writes:
Scary. Anyone who did A level chemistry forty or fifty years ago
would
have been very well aware of the risks. Now you have to have safety
screens when the teacher is using dilute acids. Somewhere along the
way
we lost the science.

I'm told practicals are a thing of the past in most schools,
not due to H&S, but due to no time left after covering everything
that's centrally mandated nowadays.

However, it reminds me of a lecture at university, Materials Science
topic. Lecturer started with a balloon (blown up) in one hand, and
a pin in the other, and jokingly said
"I should really have a safety screen for this!"
When he stuck the pin in the balloon and it burst, the knot shot off
and got me in the eye, which was quite painful.

;-)

I am sure we did plenty of things at school that were dodgy then - let
alone now...

Making Nitrogen Triiodide was fun (we were allowed to make it on the
understanding none of it left the lab... not sure is there were any of
us that did not spirit at least some out!)

I think you mean ammonium tri-iodide made by dissolving iodine in 880
ammonia solution.

Indeed another name for the same thing... NI3

(IIRC we made it with crystallized iodine, which then allows you to pour
off the amonia once "activated" - its then stable so long as its kept
wet)

aka Nitrogen iodide, Ammonia triiodide, Triiodine nitride, and others...

This forms a brown precipitate that is incredibly
unstable particularly when dried.

Yes and nice puff of purple smoke... and a yellow stain on anything that
it detonates on.

Indeed but as I recall it was NH4I3 but there is some doubt because it
is so unstable it is very hard to work with.

Yup there do seem to be various conflicting references.

Thought this one was quite nice:

http://www.chm.bris.ac.uk/motm/ni3/ni3j.htm




--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 17/08/2012 17:52, Andrew Gabriel wrote:
Actually, looking
back, our chemistry teachers allowed us to do some quite risky
things like dropping sodium into acid (by a remote control scheme
we had to build for the purpose). That was really spectacular,
and we could see why the text books all say to never do this.

Ah, yes. I remember one teacher showing us about phosphorus and sodium,
and how you store the former in a jar of water, and the latter in a jar
of oil, "...and make sure you never get them muddled up! ha ha!" and
then proceeded to do precisely that, topping up the sodium jar from the
tap...

"RUN!!!"

Fortunately no injury or major damage resulted.

David

"John Rumm" wrote in message
o.uk...
On 15/08/2012 21:40, Andrew Gabriel wrote:
In article m,
newshound writes:
Scary. Anyone who did A level chemistry forty or fifty years ago would
have been very well aware of the risks. Now you have to have safety
screens when the teacher is using dilute acids. Somewhere along the way
we lost the science.

I'm told practicals are a thing of the past in most schools,
not due to H&S, but due to no time left after covering everything
that's centrally mandated nowadays.

However, it reminds me of a lecture at university, Materials Science
topic. Lecturer started with a balloon (blown up) in one hand, and
a pin in the other, and jokingly said
"I should really have a safety screen for this!"
When he stuck the pin in the balloon and it burst, the knot shot off
and got me in the eye, which was quite painful.

;-)

I am sure we did plenty of things at school that were dodgy then - let
alone now...

Making Nitrogen Triiodide was fun (we were allowed to make it on the
understanding none of it left the lab... not sure is there were any of us
that did not spirit at least some out!)

Oh the joys of making NTI !! Pure iodine crystals stolen from the biology
lab at lunchtime. For some reason that I can't remember now, they didn't
have iodine crystals on the shelf in the chem labs. The very best ammonia
for making the NTI was a household cleaner called Handy Andy. We used to
make the stuff by the boiling tube-full. Quite safe as long as it was moist,
but a quite potent mix when dry ... We used to splatter it along corridors,
and then wait for the bangs and clouds of purple smoke when it dried and got
trod on. It all came to a halt when someone put a bloody great blob of the
stuff where the head marched from his office and onto the stage in the hall
for morning assembly every day. There was a huge bang when he stood on it
and a bloody great cloud of smoke. He went mad and started screaming about
thrashing the individuals responsible to "within an inch of their miserable
lives" !! Oh happy days ... :-)


A demo of converting copper coins into "silver" by rubbing with Millon's
Solution (a Mercury and Nitric acid reagent IIRC) - apparently this was a
technique that kept the teacher in question in cheap beer at a local pub
through his university days, due to the peculiarities of pre decimal
coinage.

It was an old halfpenny and bottle number 32, which was, ISTR, mercuric
nitrate. First, you cleaned the ha'penny using nitric acid. You then doused
it in the mercuric nitrate, and when you took it out, it had taken on a nice
silver finish. As this coin was quite similar in size to a shilling - 24
times the value - it was easy to pass off your 'treated' ha'penny in the
shop up the road to buy your fags, or whatever. Trouble was, the coating
didn't last, and by the time the shopkeeper came to cash up, it had gone,
and his shilling till compartment mysteriously had several copper coins in
it ...

We got away with it for quite a while before he twigged and banned us from
his shop. Nice bloke. Pete his name was ...

Arfa



The manufacture of bromide gas was also entertaining when someone forgot
to hook the reaction vessel up to the gas jar and filled the lab instead
;-)

And chucking various reactive metals in water was always fun.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

"Andrew Gabriel" wrote in message
...
In article ,
John Rumm writes:
On 15/08/2012 21:40, Andrew Gabriel wrote:
In article m,
newshound writes:
Scary. Anyone who did A level chemistry forty or fifty years ago would
have been very well aware of the risks. Now you have to have safety
screens when the teacher is using dilute acids. Somewhere along the way
we lost the science.

I'm told practicals are a thing of the past in most schools,
not due to H&S, but due to no time left after covering everything
that's centrally mandated nowadays.

However, it reminds me of a lecture at university, Materials Science
topic. Lecturer started with a balloon (blown up) in one hand, and
a pin in the other, and jokingly said
"I should really have a safety screen for this!"
When he stuck the pin in the balloon and it burst, the knot shot off
and got me in the eye, which was quite painful.

;-)

I am sure we did plenty of things at school that were dodgy then - let
alone now...

Making Nitrogen Triiodide was fun (we were allowed to make it on the
understanding none of it left the lab... not sure is there were any of
us that did not spirit at least some out!)

I made it at home, Scrubbs household ammonia, Iodine, and tincture
of iodine (potassium iodide solution) bought from the chemist.

Due to my impatience waiting for it to dry, I managed to flick a
fair amount of it on the floor before it was dry, which resulted
in an interesting crackling effect later when walking over it.

Normally it was pretty harmless, but someone did manage to make
enough in the fume cupboard that it blow up the filter funnel when
it was later being cleared away. I think words were said at that
point, but it was very much about being more careful, and not
dampening the enthusiasm for such activities. Actually, looking
back, our chemistry teachers allowed us to do some quite risky
things like dropping sodium into acid (by a remote control scheme
we had to build for the purpose). That was really spectacular,
and we could see why the text books all say to never do this.
One of the chemistry teachers had a license to manufacture
fireworks (and did so regularly), so they were well aware of the
dangers, but also the enthusiasm they could generate in the subject.

A demo of converting copper coins into "silver" by rubbing with Millon's
Solution (a Mercury and Nitric acid reagent IIRC) - apparently this was
a technique that kept the teacher in question in cheap beer at a local
pub through his university days, due to the peculiarities of pre decimal
coinage.

The manufacture of bromide gas was also entertaining when someone forgot
to hook the reaction vessel up to the gas jar and filled the lab instead
;-)

And chucking various reactive metals in water was always fun.

In my brother's year, there used to be a game of "chicken" which
played out during chemistry lessons. At the start, someone got a
beaker out of the cupboard, and poured some chemical into it from
the bench (we had lots of chemical reagent bottles on the benches,
although nothing particularly harmful was left out permanently).
The beaker was passed on to the next person to add some other
chemical. If you were lucky, nothing much happened. If you were
unlucky, it frothed up all over the bench, and you then had to
hide the mess or if noticed, quickly think of a pausible excuse.

I just can't imagine any of this happening today. Chemistry must
be very boring...

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

If you pulled the gas tube off the Bunsen burner in the cupboard by your
feet, it fitted very nicely onto a pipette. If you then put the other end
onto a bench water tap, you could fire a jet of water probably 15 feet to
get the class swat on the back of the head. One day, my experiment partner,
'Zuni' Curtis ( remember Zuni on Fireball XL5 ? ) performed this trick, but
turned the tap on so hard, the pipette shot out of the end of the pipe, and
through his hand. It flew across the lab like a rocket, to shatter on the
floor just in front of the teacher's podium ... Saturday morning
detentions all round ...

Arfa

John Rumm wrote:
On 17/08/2012 18:36, Peter Crosland wrote:
On 17/08/2012 16:30, John Rumm wrote:
On 15/08/2012 21:40, Andrew Gabriel wrote:
In article m,
newshound writes:
Scary. Anyone who did A level chemistry forty or fifty years ago would
have been very well aware of the risks. Now you have to have safety
screens when the teacher is using dilute acids. Somewhere along the
way
we lost the science.

I'm told practicals are a thing of the past in most schools,
not due to H&S, but due to no time left after covering everything
that's centrally mandated nowadays.

However, it reminds me of a lecture at university, Materials Science
topic. Lecturer started with a balloon (blown up) in one hand, and
a pin in the other, and jokingly said
"I should really have a safety screen for this!"
When he stuck the pin in the balloon and it burst, the knot shot off
and got me in the eye, which was quite painful.

;-)

I am sure we did plenty of things at school that were dodgy then - let
alone now...

Making Nitrogen Triiodide was fun (we were allowed to make it on the
understanding none of it left the lab... not sure is there were any of
us that did not spirit at least some out!)

I think you mean ammonium tri-iodide made by dissolving iodine in 880
ammonia solution.

Indeed another name for the same thing... NI3

(IIRC we made it with crystallized iodine, which then allows you to pour
off the amonia once "activated" - its then stable so long as its kept wet)

aka Nitrogen iodide, Ammonia triiodide, Triiodine nitride, and others...

This forms a brown precipitate that is incredibly
unstable particularly when dried.

Yes and nice puff of purple smoke... and a yellow stain on anything that
it detonates on.


Put a small quantity in a lock wait to dry and watch someone insert a
key ( we did stupid things when young)

In message , Andrew Gabriel
writes

Making Nitrogen Triiodide was fun (we were allowed to make it on the
understanding none of it left the lab... not sure is there were any of
us that did not spirit at least some out!)

I made it at home, Scrubbs household ammonia, Iodine, and tincture
of iodine (potassium iodide solution) bought from the chemist.

Due to my impatience waiting for it to dry, I managed to flick a
fair amount of it on the floor before it was dry, which resulted
in an interesting crackling effect later when walking over it.

Normally it was pretty harmless, but someone did manage to make
enough in the fume cupboard that it blow up the filter funnel when
it was later being cleared away.

I made some on a semi-industrial scale at uni

I had a demijohn of ammonia 880 and a ruck of iodine - boiled them up
together and left the half inch of it under water in a jam jar in the
shed for a couple of days

Walked into the kitchen with it and suddenly, inevitably ...

BOOM !

The kitchen ceiling and floor turned purple and all I had left was the,
still intact, screw thread of the jam jar

I now know that ammonia tri-iodide becomes unstable with time

--
geoff

In message , "Alan (BigAl)"
writes


I am sure we did plenty of things at school that were dodgy then - let
alone now...

Thanks for putting me in mind of school chemistry lessons.

Our chemistry teacher was employed during the war in
munitions/explosives development. He was responsible for my interest in
the subject, leading to a lifetime working in jobs related to chemistry.

At the end of the year, when there was a lul after exams and before the
formal end of term, he would carry out some practical demonstrations
which served to educate, but also entertain. The most vigourous of
which (as I remember from 40+ years ago) was creating some thermite in
a bucket at the back of the lab out of the view of the other school
buildings.

The big bang and the huge cloud of smoke gave him away, however. His
palour and reaction to the event told us he got the proportions wrong,
and I doubt he repeated the trick. It was entertaining though.

We actually had a rocket club at school

We built one out of fireworks and, in front of half the school, it was
set off by the school chaplain. It rose 50 feet then something fell off
and it shot off horizontally down the mall for half a mile before belly
flopping on to the grass

Of course having a school chaplain who was the only person to hold a
private firework licence helped [1], but it just wouldn't happen
nowadays, would it ?

[1] - http://www.kimboltonfireworks.co.uk/
--
geoff

In message , John
Rumm writes
(IIRC we made it with crystallized iodine, which then allows you to
pour off the amonia once "activated" - its then stable so long as its
kept wet)

Err no - see my post


--
geoff

In message , geoff
writes
We built one out of fireworks and, in front of half the school, it was
set off by the school chaplain. It rose 50 feet then something fell off
and it shot off horizontally down the mall for half a mile before belly
flopping on to the grass

Of course having a school chaplain who was the only person to hold a
private firework licence helped [1], but it just wouldn't happen
nowadays, would it ?

[1] - http://www.kimboltonfireworks.co.uk/


I went to one of his talks on fireworks years ago, he was brilliant,
nothing too technical, but a lot of stories similar to yours. He made
it sound a very interesting subject.
--
Bill

In message , geoff
writes
In message , John
Rumm writes
(IIRC we made it with crystallized iodine, which then allows you to
pour off the amonia once "activated" - its then stable so long as its
kept wet)

Err no - see my post

Seconded.

I made a 1/2" test tube of it at school. I carried it home in my
pocket and put it in a locker in my workshop. I had my own workshop
from about age 14, great fun. Any way a couple of days later I opened
the locker and it was a strange yellow/purple colour and the test tube
had disappeared. It had done this all by itself with no external
influences.

Dangerous stuff.

But fun :-)





--
Bill

In message , Bill
writes
In message , geoff
writes
We built one out of fireworks and, in front of half the school, it was
set off by the school chaplain. It rose 50 feet then something fell
off and it shot off horizontally down the mall for half a mile before
belly flopping on to the grass

Of course having a school chaplain who was the only person to hold a
private firework licence helped [1], but it just wouldn't happen
nowadays, would it ?

[1] - http://www.kimboltonfireworks.co.uk/


I went to one of his talks on fireworks years ago, he was brilliant,
nothing too technical, but a lot of stories similar to yours. He made
it sound a very interesting subject.

Yes, he was a good chemistry teacher too


--
geoff

On 18/08/2012 23:12, Bill wrote:
In message , geoff
writes
In message , John
Rumm writes
(IIRC we made it with crystallized iodine, which then allows you to
pour off the amonia once "activated" - its then stable so long as its
kept wet)

Err no - see my post

Seconded.


Perhaps we never kept any that long ;-)




--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

"John Rumm" wrote in message
...
On 18/08/2012 23:12, Bill wrote:
In message , geoff
writes
In message , John
Rumm writes
(IIRC we made it with crystallized iodine, which then allows you to
pour off the amonia once "activated" - its then stable so long as its
kept wet)

Err no - see my post

Seconded.


Perhaps we never kept any that long ;-)




--
Cheers,

John.


I know that I never did. It was made, splatted around, and detonated by
unsuspecting souls within hours ... !!

Arfa

On 18/08/2012 22:20, geoff wrote:
In message , Andrew Gabriel
writes

Making Nitrogen Triiodide was fun (we were allowed to make it on the
understanding none of it left the lab... not sure is there were any of
us that did not spirit at least some out!)

I made it at home, Scrubbs household ammonia, Iodine, and tincture
of iodine (potassium iodide solution) bought from the chemist.

Due to my impatience waiting for it to dry, I managed to flick a
fair amount of it on the floor before it was dry, which resulted
in an interesting crackling effect later when walking over it.

Normally it was pretty harmless, but someone did manage to make
enough in the fume cupboard that it blow up the filter funnel when
it was later being cleared away.

I made some on a semi-industrial scale at uni

I had a demijohn of ammonia 880 and a ruck of iodine - boiled them up
together and left the half inch of it under water in a jam jar in the
shed for a couple of days

Walked into the kitchen with it and suddenly, inevitably ...

BOOM !

The kitchen ceiling and floor turned purple and all I had left was the,
still intact, screw thread of the jam jar

I now know that ammonia tri-iodide becomes unstable with time


OK, I think that's my cue to pull my ammonium tri-iodide / toilet story
from the archives, for anyone who hasn't seen it...

https://groups.google.com/d/msg/uk.d-i-y/LRI4OCJD8a4/EuBczHsmK3IJ

David

In message , Lobster
writes

OK, I think that's my cue to pull my ammonium tri-iodide / toilet story
from the archives, for anyone who hasn't seen it...

https://groups.google.com/d/msg/uk.d-i-y/LRI4OCJD8a4/EuBczHsmK3IJ

David



On a slightly different tack, but equally amusing, but not at the time,
and certainly not now that I am a responsible adult of course......

While in the 6th for at school we had been given a gas liquid
chromatograph by a local company, at about the same time we had also
been given the contents of a local research companies labs. Lots and
lots of brown glass bottles of various interesting substances.

Any way being in a hurry to play with the GLC, we tried it without
fitting the exhaust pipe work to a suitable external vent. We ran a few
substances through it and got the expected traces on the plotter, then
came a bottle that we didn't recognise, in it went, I never actually
saw the plot because all of a sudden my eyes closed up, as did those of
the other guy in the room. we managed to make it out of the room, more
by feel than anything else, and get to a wash room and rinse our eyes
out. When we regained our sight we noticed that there was a large
number of pupils all standing around outside rubbing their eyes too.
Plus a couple of rather ****ed off teachers. We'd managed to empty the
whole block of classrooms.

Apparently what ever it was we had put through the GLC was the main
constituent part of a WW1 tear gas, it was certainly effective.

The chemistry teacher believed us when we said it was not intentional
and promptly disposed of the remainder of the chemical by pouring it
down the drain...

How things have changed over the years...................
--
Bill

In message , Lobster
writes
On 18/08/2012 22:20, geoff wrote:
In message , Andrew Gabriel
writes

Making Nitrogen Triiodide was fun (we were allowed to make it on the
understanding none of it left the lab... not sure is there were any of
us that did not spirit at least some out!)

I made it at home, Scrubbs household ammonia, Iodine, and tincture
of iodine (potassium iodide solution) bought from the chemist.

Due to my impatience waiting for it to dry, I managed to flick a
fair amount of it on the floor before it was dry, which resulted
in an interesting crackling effect later when walking over it.

Normally it was pretty harmless, but someone did manage to make
enough in the fume cupboard that it blow up the filter funnel when
it was later being cleared away.

I made some on a semi-industrial scale at uni

I had a demijohn of ammonia 880 and a ruck of iodine - boiled them up
together and left the half inch of it under water in a jam jar in the
shed for a couple of days

Walked into the kitchen with it and suddenly, inevitably ...

BOOM !

The kitchen ceiling and floor turned purple and all I had left was the,
still intact, screw thread of the jam jar

I now know that ammonia tri-iodide becomes unstable with time


OK, I think that's my cue to pull my ammonium tri-iodide / toilet story
from the archives, for anyone who hasn't seen it...

https://groups.google.com/d/msg/uk.d-i-y/LRI4OCJD8a4/EuBczHsmK3IJ

Don't remember that one, but interesting to note that some of us are
repeating exactly the same stories in this thread that we told 9 years
ago

--
geoff

In message , Arfa Daily
writes

I know that I never did. It was made, splatted around, and detonated by
unsuspecting souls within hours ... !!


No wonder kids today go around vandalising things - that's all the
excitement they get in their otherwise cosseted lives


--
geoff

"Arfa Daily" wrote in message
...


"John Rumm" wrote in message
o.uk...
On 15/08/2012 21:40, Andrew Gabriel wrote:
In article m,
newshound writes:
Scary. Anyone who did A level chemistry forty or fifty years ago would
have been very well aware of the risks. Now you have to have safety
screens when the teacher is using dilute acids. Somewhere along the way
we lost the science.

I'm told practicals are a thing of the past in most schools,
not due to H&S, but due to no time left after covering everything
that's centrally mandated nowadays.

However, it reminds me of a lecture at university, Materials Science
topic. Lecturer started with a balloon (blown up) in one hand, and
a pin in the other, and jokingly said
"I should really have a safety screen for this!"
When he stuck the pin in the balloon and it burst, the knot shot off
and got me in the eye, which was quite painful.

;-)

I am sure we did plenty of things at school that were dodgy then - let
alone now...

Making Nitrogen Triiodide was fun (we were allowed to make it on the
understanding none of it left the lab... not sure is there were any of us
that did not spirit at least some out!)

Oh the joys of making NTI !! Pure iodine crystals stolen from the biology
lab at lunchtime. For some reason that I can't remember now, they didn't
have iodine crystals on the shelf in the chem labs. The very best ammonia
for making the NTI was a household cleaner called Handy Andy. We used to
make the stuff by the boiling tube-full. Quite safe as long as it was
moist, but a quite potent mix when dry ... We used to splatter it along
corridors, and then wait for the bangs and clouds of purple smoke when it
dried and got trod on. It all came to a halt when someone put a bloody
great blob of the stuff where the head marched from his office and onto
the stage in the hall for morning assembly every day. There was a huge
bang when he stood on it and a bloody great cloud of smoke. He went mad
and started screaming about thrashing the individuals responsible to
"within an inch of their miserable lives" !! Oh happy days ... :-)


A demo of converting copper coins into "silver" by rubbing with Millon's
Solution (a Mercury and Nitric acid reagent IIRC) - apparently this was a
technique that kept the teacher in question in cheap beer at a local pub
through his university days, due to the peculiarities of pre decimal
coinage.

It was an old halfpenny and bottle number 32, which was, ISTR, mercuric
nitrate. First, you cleaned the ha'penny using nitric acid. You then
doused it in the mercuric nitrate, and when you took it out, it had taken
on a nice silver finish. As this coin was quite similar in size to a
shilling - 24 times the value - it was easy to pass off your 'treated'
ha'penny in the shop up the road to buy your fags, or whatever. Trouble
was, the coating didn't last, and by the time the shopkeeper came to cash
up, it had gone, and his shilling till compartment mysteriously had
several copper coins in it ...

Electroplate with silver nitrate then.

"Jake" wrote in message
...

"Arfa Daily" wrote in message
...


"John Rumm" wrote in message
o.uk...
On 15/08/2012 21:40, Andrew Gabriel wrote:
In article m,
newshound writes:
Scary. Anyone who did A level chemistry forty or fifty years ago would
have been very well aware of the risks. Now you have to have safety
screens when the teacher is using dilute acids. Somewhere along the
way
we lost the science.

I'm told practicals are a thing of the past in most schools,
not due to H&S, but due to no time left after covering everything
that's centrally mandated nowadays.

However, it reminds me of a lecture at university, Materials Science
topic. Lecturer started with a balloon (blown up) in one hand, and
a pin in the other, and jokingly said
"I should really have a safety screen for this!"
When he stuck the pin in the balloon and it burst, the knot shot off
and got me in the eye, which was quite painful.

;-)

I am sure we did plenty of things at school that were dodgy then - let
alone now...

Making Nitrogen Triiodide was fun (we were allowed to make it on the
understanding none of it left the lab... not sure is there were any of
us that did not spirit at least some out!)

Oh the joys of making NTI !! Pure iodine crystals stolen from the biology
lab at lunchtime. For some reason that I can't remember now, they didn't
have iodine crystals on the shelf in the chem labs. The very best ammonia
for making the NTI was a household cleaner called Handy Andy. We used to
make the stuff by the boiling tube-full. Quite safe as long as it was
moist, but a quite potent mix when dry ... We used to splatter it along
corridors, and then wait for the bangs and clouds of purple smoke when it
dried and got trod on. It all came to a halt when someone put a bloody
great blob of the stuff where the head marched from his office and onto
the stage in the hall for morning assembly every day. There was a huge
bang when he stood on it and a bloody great cloud of smoke. He went mad
and started screaming about thrashing the individuals responsible to
"within an inch of their miserable lives" !! Oh happy days ...
:-)


A demo of converting copper coins into "silver" by rubbing with Millon's
Solution (a Mercury and Nitric acid reagent IIRC) - apparently this was
a technique that kept the teacher in question in cheap beer at a local
pub through his university days, due to the peculiarities of pre decimal
coinage.

It was an old halfpenny and bottle number 32, which was, ISTR, mercuric
nitrate. First, you cleaned the ha'penny using nitric acid. You then
doused it in the mercuric nitrate, and when you took it out, it had taken
on a nice silver finish. As this coin was quite similar in size to a
shilling - 24 times the value - it was easy to pass off your 'treated'
ha'penny in the shop up the road to buy your fags, or whatever. Trouble
was, the coating didn't last, and by the time the shopkeeper came to cash
up, it had gone, and his shilling till compartment mysteriously had
several copper coins in it ...

Electroplate with silver nitrate then.


Ah, but that needs setting up. Bottle 32'ing could be done in a few minutes
at lunchtime with one of us doing the lab work, and another keeping watch.
And it lasted long enough to be able to swing the coins across the local
shopkeeper, so that was good enough ... :-)

Arfa

In article ,
geoff writes:
I made some on a semi-industrial scale at uni

I had a demijohn of ammonia 880 and a ruck of iodine - boiled them up
together and left the half inch of it under water in a jam jar in the
shed for a couple of days

Don't need to boil - just add a little potassium iodide, which
makes the iodine react with ammonia quite quickly at room temp.

Walked into the kitchen with it and suddenly, inevitably ...

BOOM !

The kitchen ceiling and floor turned purple and all I had left was the,
still intact, screw thread of the jam jar

I now know that ammonia tri-iodide becomes unstable with time

Apparently (according to wikipedia), even a alpha particle can
trigger it.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In article , Tim Streater wrote:
In article ,
(Andrew Gabriel) wrote:
In article ,
geoff writes:

I now know that ammonia tri-iodide becomes unstable with time

Apparently (according to wikipedia), even a alpha particle can
trigger it.

Nitrogen tri-iodide. And if can be triggered by alpha particles, that
means essentially spontaneous, as alphas have no penetrating power. Thus
it would have to be an alpha generated by some radioactive impurity
within the mixture.

With exceptions: http://en.wikipedia.org/wiki/Alpha_particle
"As noted, the helium nuclei that form 10-12% of cosmic rays are also usually
of much higher energy than those produced by nuclear decay processes, and are
thus capable of being highly penetrating and able to traverse the human body
and also many meters of dense solid shielding, depending on their energy."

(The reference on the NI3 page isn't talking about that, but if it can be
triggered by an alpha from an accelerator, then perhaps it can be triggered
by a much higher energy one.)

This thread prompted me to check my "stash" from my schooldays (40+
years ago).

I still have a 100cc bottle full of mercury. Some was pinched from
school but most was given to me by my gran - she had it from the days
when you bought your own to take to the dentist for amalgam fillings. I
really ought to dispose of it through the right channels.

There's also a half-full 500cc jar of iodine crystals (labelled "A N
Beck, Stoke Newington"). The rest must have, over time, been mixed with
Scrubbs Cloudy Ammonia, carefully dried on blotting paper, and left in
places my sister frequented.

There's also some potassium permanganate which ISTR spontaneously
ignites with glycerine (or is it brake fluid?).

Sadly no zinc powder - that makes great cigar-tube-rocket fuel when
mixed with sulphur, or any (pre-fire-retardant) sodium chlorate which
goes up nicely with sugar, or ammonium dichromate for a "volcano".

After "A" levels we were allowed to make ethyl mercaptan at school. That
was fun.

--
Reentrant

On Monday, August 20, 2012 1:21:30 PM UTC+1, Reentrant wrote:
This thread prompted me to check my "stash" from my schooldays (40+
years ago).
I still have a 100cc bottle full of mercury. Some was pinched from
school but most was given to me by my gran - she had it from the days
when you bought your own to take to the dentist for amalgam fillings. I
really ought to dispose of it through the right channels.
There's probably someone who restores barometers who would be happy to take this - the poblem is finding them...
There's also a half-full 500cc jar of iodine crystals (labelled "A N
Beck, Stoke Newington").
I remember buying things from them. Eventually we decided that was too expensive and found a local chemical supplier who would deliver. Those were the days when you could order concentrated sulphuric acid, nitric acid, and the like and have them delivered to your house. If I remember right we were also able to buy some things through the school chemistry lab.
I still have the remains of a bottle of HF in the cellar...

On 19/08/2012 20:55, geoff wrote:
In message , Lobster
writes
On 18/08/2012 22:20, geoff wrote:
In message , Andrew Gabriel
writes

Making Nitrogen Triiodide was fun (we were allowed to make it on the
understanding none of it left the lab... not sure is there were any of
us that did not spirit at least some out!)

I made it at home, Scrubbs household ammonia, Iodine, and tincture
of iodine (potassium iodide solution) bought from the chemist.

Due to my impatience waiting for it to dry, I managed to flick a
fair amount of it on the floor before it was dry, which resulted
in an interesting crackling effect later when walking over it.

Normally it was pretty harmless, but someone did manage to make
enough in the fume cupboard that it blow up the filter funnel when
it was later being cleared away.

I made some on a semi-industrial scale at uni

I had a demijohn of ammonia 880 and a ruck of iodine - boiled them up
together and left the half inch of it under water in a jam jar in the
shed for a couple of days

Walked into the kitchen with it and suddenly, inevitably ...

BOOM !

The kitchen ceiling and floor turned purple and all I had left was the,
still intact, screw thread of the jam jar

I now know that ammonia tri-iodide becomes unstable with time


OK, I think that's my cue to pull my ammonium tri-iodide / toilet
story from the archives, for anyone who hasn't seen it...

https://groups.google.com/d/msg/uk.d-i-y/LRI4OCJD8a4/EuBczHsmK3IJ

Don't remember that one, but interesting to note that some of us are
repeating exactly the same stories in this thread that we told 9 years ago

So are any of the yarns "improving" with the telling?!

David

On 20/08/12 14:21, Reentrant wrote:
This thread prompted me to check my "stash" from my schooldays (40+
years ago).



There's also a half-full 500cc jar of iodine crystals (labelled "A N
Beck, Stoke Newington").

I remember them.


There's also some potassium permanganate which ISTR spontaneously
ignites with glycerine (or is it brake fluid?).

glycerine.

--
djc

In message , Lobster
writes
On 19/08/2012 20:55, geoff wrote:
In message , Lobster
writes
On 18/08/2012 22:20, geoff wrote:
In message , Andrew Gabriel
writes

Making Nitrogen Triiodide was fun (we were allowed to make it on the
understanding none of it left the lab... not sure is there were any of
us that did not spirit at least some out!)

I made it at home, Scrubbs household ammonia, Iodine, and tincture
of iodine (potassium iodide solution) bought from the chemist.

Due to my impatience waiting for it to dry, I managed to flick a
fair amount of it on the floor before it was dry, which resulted
in an interesting crackling effect later when walking over it.

Normally it was pretty harmless, but someone did manage to make
enough in the fume cupboard that it blow up the filter funnel when
it was later being cleared away.

I made some on a semi-industrial scale at uni

I had a demijohn of ammonia 880 and a ruck of iodine - boiled them up
together and left the half inch of it under water in a jam jar in the
shed for a couple of days

Walked into the kitchen with it and suddenly, inevitably ...

BOOM !

The kitchen ceiling and floor turned purple and all I had left was the,
still intact, screw thread of the jam jar

I now know that ammonia tri-iodide becomes unstable with time


OK, I think that's my cue to pull my ammonium tri-iodide / toilet
story from the archives, for anyone who hasn't seen it...

https://groups.google.com/d/msg/uk.d-i-y/LRI4OCJD8a4/EuBczHsmK3IJ

Don't remember that one, but interesting to note that some of us are
repeating exactly the same stories in this thread that we told 9 years ago

So are any of the yarns "improving" with the telling?!

I think I've refined the story ...


--
geoff

In article ,
says...

"John Rumm" wrote in message
...

Perhaps we never kept any that long ;-)


I know that I never did. It was made, splatted around, and detonated by
unsuspecting souls within hours ... !!


I was told this tale by someone who went to a school not far from mine
of the Speech Day in their last year when they made a large quantity
which they painted down the centre aisle of the school hall.

The entire school filed in as usual, splitting left and right and
filling the rows of seats from the side aisles.

When everybody was seated, the headmaster entered, accompanied by the
Mayor and Mayoress of West Ham, who then commenced their walk up the
central aisle ...

--

Terry